The present invention relates to plate type condenser and more particularly it relates to a condenser called the plate and shell type condenser wherein a plurality of heat transmitting plates which are assembled in side-by-side contacted relation are enclosed in a container.
In this type of condensers, a plurality of heat transmitting plates are in a side-by-side contacted relation within a container or shell with a gasket disposed between adjacent heat transmitting plates, the disposition of the gaskets being such that steam passages which suitably open to the space inside the shell and cooling liquid passages isolated from said space are alternately defined in the internal clearances of the plate assembly. The steam supplied from the steam supply port of the shell flows into the steam passages through the openings therein and cooled by the cooling liquid in the adjacent cooling liquid passages through the heat transmitting plates and thereby condensed, the resulting condensate and uncondensed steam flowing out of the final steam passage through the steam outlet opening into the shell for discharge through the steam discharge port.
It is desirable that the steam inlet to the steam passages have a large opening area so that the pressure loss of steam at said part may not increase. Further, it is necessary that the gaskets for isolating the cooling liquid passages from the space inside the shell be firmly retained so as to prevent the leakage of cooling liquid.
When steam is supplied into the shell, if there is a space between the shell and the plates, the flow of steam is divided into two streams, a normal stream which flows from the steam inlet opening via the steam passages into the steam outlet opening and then flows out of the steam discharge port of the shell and a second stream which short-passes from the steam supply port into the steam outlet port via said space between the plates and shell. Further, since the short-passed steam naturally has a higher pressure than the steam (condensate and uncondensed steam) which has passed through the steam passages, i.e., the condensing process, into the steam outlet opening, it tends to flow from the steam outlet opening back into the steam passages. As a result, the flow of steam in the steam passages is impeded and the heat transmission efficiency is greatly reduced.
Generally, steam contains uncondensable gasses, such as air, and major factors in heat transmission technology vary according to the amount of said uncondensable gases. Therefore, it is difficult or very inefficient to apply a given plate configuration to the condensation of all kinds of gases.
Further, when steam containing uncondensable gases are being condensed, as the steam flow approaches the downstream region the concentration of uncondensable gases increases with the condensation of steam and hence the heat transmission is aggravated. Therefore, in order to prevent detraction from heat transmission performance, it is necessary to take some measure to keep the concentration of uncondensable gases low throughout the heat transmission area.